RESUMO
In this study, we compared the microbiota and volatile organic compounds (VOC) present in the milk obtained from 3 different sheep breeds, namely Merino, Lacaune, and Assaf. Udder milk was collected from 21 animals, 7 from each breed. Bacterial microflora was determined metagenomically by extracting the DNA from the milk and analyzing the V3-V4 region of the 16S rRNA gene. Headspace solid-phase microextraction gas chromatography-mass spectrometry method was used to analyze VOC. The metagenomic analysis revealed (for Merino, Lacaune, and Assaf milk, respectively) Firmicutes (66.32, 69.36, and 57.08%), Actinobacteria (19.09, 7.67, and 19.40%), Proteobacteria (13.76, 21.06, and 22.19%), and Bacteroidetes (0.84, 1.91, and 1.33%) phyla in the milk samples. Lactobacillus was highly abundant in the milk of 3 breeds (29.64, 43.50, and 18.70%). The genera constituting more than 2% of all bacteria in all groups were Jeotgalicoccus (7.19, 5.34, and 10.77%), Enterococcus (5.18, 9.78, and 3.64%), and Corynebacterium (4.08, 3.00, and 13.44%). A total of 32 different VOC were identified by headspace solid-phase microextration analysis with 9, 30, and 24 different compounds from Merino, Lacaune, and Assaf breeds, respectively. Although ketone was the most abundant compound in Merino milk (71.84%), hydrocarbons were the most detected in Lacaune and Assaf milk (37.18% and 55.42%, respectively). A positive correlation was found between acetone, which was detected at the highest level in all groups, with Salinicoccus, Alloiococcus, Psychrobacter, and Dietzia. In addition, a negative correlation was found between the Lactobacillus genus, detected at the highest level in all groups, with methyl cyclopentane, 3-methylheptane, octane, decane, 3,3-dimethyloctane, and dodecane. Thus, differences were observed in the bacterial microflora and VOC in the sheep milk from different breeds under different feeding and breeding conditions.